Comparative Study on the Characteristic Occurrences of Heishang Ni-Cu Deposit in Subei County of Gansu Province

Heishan Ni-Cu deposit is situated on the Heisltan-Jiznquanzi Pault which is the south margin of Mazongshan middle block within Kazakhstan paleo-plate.The fault has the characteristics of marginal rift on the edge of paleo-plate,and regionally,the fault and rock mass appear the obvious gravity and magnetic anomaly.The ore-bearing rock body intruded into dolomite marble of Qingbaikou Series Dahuioluoshan Group,and Cambrian Shuanyingshan Fo2,slightly longer on the NW direction,about 800 m long and 470 m wide.It is a complex massif developed from multi-intrusive of the same source and period,mainly comprised of plagioharzburgite, hornblende-olivinite,olivine-hornblende-gabbro,and hornblende gabbro.The first phase is hornblende-gabbro facies which consist of hornblende-gabbro and quartz-syenite block within gabbro.The second phase is olivine-hornblende-gabbro and plagio-harzzburgite facies which consist of olivinehornblende-gabbro,hornblende-olivine-gabbro,hornblende gabbro,and plagio-harzburgite.The average of chemical composition is similar with ultrabasie rock.The basicity index gr is very low,average is 0.05, Ti0₂ 0.28m/f(Wu Liren)4.79,Zavaritskiivalues b=56.00,ε=39.77;m'=81.68;Na₂0>K₂0, the basicity type is Pacific type.The protomagma is characterized of olivine-tholeiite,came from the upper mantle.The average value of Mg/Fe is 4.79.Ni-Cu orebody with appearance of len,vein and stratiformlike mainly exist the middle and lower part of rock mass.Mother rock and ore-bearing rock mainly consist of harzbeugite,secondly hornblende-gabbro.The ore body is classified into 3 types:insitu liquation,late period injection and contact metamorphic body.The ore minerals include niecolite,chloanthite, chalcopyrite,millerite,magnetic pyrite,chalcoeite,as well as some pyrite,violarite and natural copper.The metal oxide is magnetite.The associated elements have Co,Pt,Pd,Au,Ag,Os,Ir,Ru,Rhodium,Se,Te,Cr etc.The harmful elements have Pb,Zn,As,Bi.The chemieal composition of ore is characterized of poor alkali,lower aluminium and calcium.Although a 1ittle differences of scale and neme-racalvalues,Heishan Ni-Cu deposit has the same condition with Jnehuan Ni-Cu deposit on geological setting of diagenesis and metallogensis,gravity and magnetic anomaly.occurrence of ore-bearing rock body,feature of ore body,petrochemistry and metaUogenie elements,generally,these reflected similarity and consistency of two deposits Oll diagenesis and metallogenesis.Heishan district would be expected to be potential in depth.Regionally,around the area of gravity and magnetic anomaly on the deep-great fault at the edge of archicontinent or old block,the prospecting targets for magmatie NLCu deposit should be focused on multi-phase intrusive outcrop or small scale concealed basic.uhrabasic complex body with anomaly zone of Fe,Cr,Ni,Co,V,Cu,Zn,Mn.